MIC280
Micrel
MIC280
Precision IttyBitty™ Thermal Supervisor
Final Information
General Description
The MIC280 is a digital thermal supervisor capable of mea-
suring its own internal temperature and that of a remote PN
junction. The remote junction may be an inexpensive com-
modity transistor, e.g., 2N3906, or an embedded thermal
diode such as found in Intel Pentium* II/III/IV CPUs, AMD
Athlon* CPUs, and Xilinx Virtex* FPGA's. A 2-wire SMBus*
2.0 compatible serial interface is provided for host communi-
cation. Remote temperature is measured with
±1°C
accuracy
and 9-bit to 12-bit resolution (programmable). Independent
high, low, and over-temperature thresholds are provided for
each zone.
The advanced integrating A/D converter and analog front-
end reduce errors due to noise for maximum accuracy and
minimum guardbanding. The interrupt output signals tem-
perature events to the host, including data-ready and diode
faults. Critical device settings can be locked to prevent
changes and insure failsafe operation. The clock, data, and
interrupt pins are 5V-tolerant regardless of the value of V
DD
.
They will not clamp the bus lines low even if the device is
powered down. Superior accuracy, failsafe operation, and
small size make the MIC280 an excellent choice for the most
demanding thermal management applications.
Features
• Measures local and remote temperature
• Highly accurate remote sensing
±1°C
max., 60°C to 100°C
• Superior noise immunity for reduced temperature
guardbands
• 9-bit to 12-bit temperature resolution for remote zone
• Fault queues to further reduce nuisance tripping
• Programmable high, low, and over-temperature thresh-
olds for each zone
• SMBus 2 compatible serial interface including device
timeout to prevent bus lockup
• Voltage tolerant I/O’s
• Open-drain interrupt output pin - supports SMBus Alert
Response Address protocol
• Low power shutdown mode
• Locking of critical functions to insure failsafe operation
• Failsafe response to diode faults
• Enables ACPI compliant thermal management
• 3.0V to 3.6V power supply range
• IttyBitty™ SOT23-6 package
Applications
•
•
•
•
•
•
•
Desktop, server and notebook computers
Printers and copiers
Test and measurement equipment
Thermal supervision of Xilinx Virtex FPGA's
Wireless/RF systems
Intelligent power supplies
Datacom/telecom cards
Typical Application
3V to 3.6V
3
×
10k
5
TO
SERIAL BUS
HOST
4
6
MIC280
DATA
CLK
/INT
VDD
T1
GND
1
3
2
0.1µF
ceramic
1800pF
2N3906/
CPU DIODE
MIC280 Typical Application
IttyBiity is a trademark of Micrel, Inc.
*All trademarks are the property of their respective owners.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
June 2001
1
MIC280
MIC280
Micrel
Ordering Information
Part Number
MIC280-0BM6
MIC280-1BM6
MIC280-2BM6
MIC280-3BM6
MIC280-4BM6
MIC280-5BM6
MIC280-6BM6
MIC280-7BM6
Marking
TA00
TA01
TA02
TA03
TA04
TA05
TA06
TA07
Slave Address
100 1000
b
100 1001
b
100 1010
b
100 1011
b
100 1100
b
100 1101
b
100 1110
b
100 1111
b
Ambient Temp. Range
–55°C to +125°C
–55°C to +125°C
–55°C to +125°C
–55°C to +125°C
–55°C to +125°C
–55°C to +125°C
–55°C to +125°C
–55°C to +125°C
Package
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
SOT23-6
Pin Configuration
VDD 1
GND 2
T1 3
6 /INT
5 DATA
4 CLK
SOT23-6
Pin Description
Pin Number
1
2
3
4
5
6
Pin Name
VDD
GND
T1
CLK
DATA
/INT
Pin Function
Power Supply Input.
Ground.
Analog Input. Connection to remote diode junction.
Digital Input. Serial bit clock input.
Digital Input/Output. Open-drain. Serial data input/output.
Digital Output. Open-drain. Interrupt output.
MIC280
2
June 2001
MIC280
Micrel
Absolute Maximum Ratings
(Note 1)
Power Supply Voltage, V
DD ...................................................
3.8V
Voltage on T1 ........................................ –0.3V to V
DD
+0.3V
Voltage on CLK, DATA, /INT ............................ –0.3V to 6V
Current Into Any Pin .................................................
±10mA
Power Dissipation, T
A
= 125°C ............................... 109mW
Storage Temperature ............................... –65°C to +150°C
ESD Ratings,
Note 3
Human Body Model ................................................ 1.5kV
Machine Model ........................................................ 200V
Soldering (SOT23-6 Package)
Vapor Phase (60s) .................................... 220°C
+5
/
-0
°C
Infrared (15s) ............................................. 235°C
+5
/
-0
°C
Operating Ratings
(Note 2)
Power Supply Voltage, V
DD ..................................
+3V to +3.6V
Ambient Temperature Range (T
A
) ........... –55°C to +125°C
Junction Temperature ............................................... 150°C
Package Thermal Resistance (θ
JA
)
SOT23-6 ............................................................ 230°C/W
Electrical Characteristics
For typical values T
A
= 25°C, V
DD
=
3.3V, unless otherwise noted.
Bold
values indicate –55°C
≤
T
A
≤
125°C, 3.0V
≤
V
DD
≤
3.6V, unless otherwise noted.
Note 2
Symbol
Parameter
Conditions
Power Supply
I
DD
Supply Current
/INT, T1 open; CLK = DATA = High;
Normal Mode
Shutdown Mode; /INT, T1 open;
Note 5
CLK = 100kHz, DATA = High
Shutdown Mode; /INT, T1 open;
CLK = DATA = High
t
POR
V
POR
V
HYST
Power-on Reset Time,
Note 5
Power-on Reset Voltage
Power-on Reset Hysteresis Voltage
Note 5
60°C
≤
T
D
≤
100°C,
3.15V < V
DD
< 3.45V, 25°C < T
A
< 85°C
0°C
≤
T
D
≤
100°C,
3.15V < V
DD
< 3.45V, 25°C < T
A
< 85°C
–55°C
≤
T
D
≤
125°C,
3.15V < V
DD
< 3.45V, 25°C < T
A
< 85°C
Accuracy, Local Temperature
Note 2, 10
0°C
≤
T
A
≤
100°C, 3.15V < V
DD
< 3.45V
–55°C
≤
T
A
≤
125°C, 3.15V < V
DD
< 3.45V
t
CONV
Conversion Time,
Notes 2, 8
RES[1:0]=00 (9 bits)
RES[1:0]=01 (10 bits)
RES[1:0]=10 (11 bits)
RES[1:0]=11 (12 bits)
Remote Temperature Input, T1
I
F
Current into External Diode
Note 5
T1 forced to 1.0V, High level
Low level
7
192
12
400
µA
µA
V
DD
> V
POR
All registers reset to default values;
A/D conversions initiated
0.23
9
6
200
2.65
300
2.95
[TBD]
0.4
mA
µA
µA
µs
V
mV
Min.
Typ
Max
Units
Temperature-to-Digital Converter Characteristics
Accuracy, Remote Temperature
Notes 2, 7, 10, 11
±0.25
±1
±2
±1
±1.5
200
330
570
1000
±
1
±
2
±
4
±
2
±
2.5
240
390
670
1250
°C
°C
°C
°C
°C
ms
ms
ms
ms
June 2001
3
MIC280
MIC280
Symbol
Parameter
Condition
Min
Typ
Max
Micrel
Units
Serial Data I/O Pin, DATA
V
OL
V
IL
V
IH
C
IN
I
LEAK
V
IL
V
IH
C
IN
I
LEAK
V
OL
t
INT
Low Output Voltage,
Note 4
I
OL
= 3mA
I
OL
= 6mA
Low Input Voltage
High Input Voltage
Input Capacitance
Input Current
3V
≤
V
DD
≤
3.6V
3V
≤
V
DD
≤
3.6V
Note 5
2.1
10
3V
≤
V
DD
≤
3.6V
3V
≤
V
DD
≤
3.6V
Note 5
2.1
10
0.3
0.5
0.8
5.5
V
V
V
V
pF
µA
±
1
0.8
5.5
Serial Clock Input, CLK
Low Input Voltage
High Input Voltage
Input Capacitance
Input Current
V
V
pF
µA
±
1
I
OL
= 3mA
I
OL
= 6mA
from TEMPx < TLOWx or
TEMPx > THIGHx or TEMPx >
CRITx to /INT < V
OL
; R
PULLUP
= 10kΩ
from read of STATUS or A.R.A. to
/INT > V
OH
; R
PULLUP
= 10kΩ
0.3
0.5
[t
CONV
]
Interrupt Output, /INT
Low Output Voltage,
Note 4
V
V
ms
Interrupt Propagation Delay
Notes 5, 6
Interrupt Reset Propagation Delay
Note 5, 9
t
nINT
I
LEAK
1
µs
µA
µs
ns
ns
ns
ns
±
1
CLK (Clock) Period
Data In Setup Time to CLK High
Data Out Stable after CLK Low
Data Low Setup Time to CLK Low
Data High Hold Time after CLK
High
Bus Timeout
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating range. Final test on outgoing product is performed at T
A
= 25°C.
Devices are ESD sensitive. Handling precautions recommended.
Current into the /INT or DATA pins will result in self heating of the device. Sink current should be minimized for best accuracy.
Guaranteed by design over the operating temperature range. Not 100% production tested.
t
INT
and t
CRIT
are equal to t
CONV
.
T
D
is the temperature of the remote diode junction. Testing is performed using a single unit of one of the transistors listed in Table 8.
Serial Interface Timing
t
1
t
2
t
3
t
4
t
5
t
TO
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Note 6.
Note 7.
Note 8.
Note 9.
2.5
100
300
Start Condition
Stop Condition
100
100
25
30
35
ms
t
CONV
= t
CONV
(local) + t
CONV
(remote). Following the acquisition of either remote or local temperature data, the limit comparisons for that zone
are performed and the device status updated; Status bits will be set and /INT driven active, if applicable.
The interrupt reset propogation delay is dominated by the capacitance on the bus.
Note 10.
Accuracy specification does not include quantization noise, which may be up to
±
1
/
2
LSB.
Note 11.
Tested at 10-bit resolution.
MIC280
4
June 2001
MIC280
Micrel
Timing Diagrams
t
1
CLK
t
4
DATA INPUT
t
3
DATA OUTPUT
Serial Interface Timing
t
2
t
5
June 2001
5
MIC280
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